Concern has been growing in recent days over energy consumption in the United States and abroad. The cost of energy has steadily risen as power utilities try to cope with continually growing demand, increasing fuel prices, and stricter regulatory mandates. Power utilities must also maintain existing infrastructure, while simultaneously finding ways to add more generation capacity to meet future needs, both of which add to the cost of energy. Moreover, burgeoning energy consumption continues to impact the environment and deplete natural resources.
Such concerns underlie industry and governmental efforts to strive for a more efficient balance between energy consumption and supply. For example, the Zero Net Energy (ZNE) initiative, backed by the U.S. Department of Energy, promotes the goal of balancing the total energy used by a building annually with the total energy generated on-site. In California, the 2013 Integrated Energy Policy Report (IEPR) builds on earlier ZNE goals by mandating that all new residential and commercial construction be ZNE-compliant, respectively, by 2020 and 2030. The IEPR defines a building as consuming zero net energy if the net amount of energy produced by renewable energy resources on-site roughly equals the value of the energy consumed by the building annually.
As the principal source of energy for most consumers, power utilities and energy agencies are at the forefront of energy efficiency initiatives, such as ZNE. These organizations often reach out to their customers through educational and incentive programs that are frequently pitched as ways to lower monthly energy bills. Typically, they urge energy conservation by cutting down on and avoiding wasteful energy use and by switching to energy efficient fixtures. They also often promote the on-site adoption of alternative sources of renewable energy.
Lowering monthly utility bills, however, is just a part of the broader problem of balancing energy consumption against supply. The average consumer continually consumes energy, whether electricity, natural gas, or other source; electricity may be purchased from the power utility or, less frequently, generated on-site. At home, energy may be used for space heating and cooling, lighting, cooking, powering appliances and electrical devices, heating water, and doing laundry. Energy may also be consumed for personal transportation needs, whether by private conveyance or public mass transit.
To raise energy awareness, power utilities often provide periodic energy consumption statistics that are gathered through the use of smart power meters or similar technologies. Such statistics, though, invariably reflect net power consumption based only upon the energy purchased from the power utility. Energy generated (and consumed) on-site is not included, as utilities currently lack practicable ways of gathering and aggregating on-site energy production and consumption values into their own power consumption statistics, in part, due to the vagaries in end-consumer equipment and energy consumption patterns.
Utility-provided net power consumption statistics can mask the overall efficiency of a building, particularly where on-site power generation and consumption significantly contributes to gross energy load. Effective energy balancing requires decreasing the amount of energy consumed and generating energy on-site. Performing both of these steps is crucial to lowering gross energy load, yet determining how efficiently energy is consumed is often skipped when a switch to an alternative energy source is made first. For instance, the installation of a photovoltaic (PV) system on a private residence frequently leads a consumer to (erroneously) conclude that further efforts at increasing energy efficiency are no longer necessary or worthwhile. The immediacy of lower monthly utility bills and favorable net power consumption statistics can reinforce this misperception.
Therefore, a need remains for an approach to empowering consumers, particularly residential customers, with full knowledge of actual gross energy consumption and an understanding what options and alternatives work best for their energy needs, especially in situations where renewable energy sources are already in place.